#define _CRT_SECURE_NO_WARNINGS 1

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    int ret = 0;
    int findTilt(TreeNode* root) {
        findT(root);

        return ret;
    }

    int findT(TreeNode* root)
    {
        if (root == nullptr)
            return 0;

        int left = findT(root->left);
        int right = findT(root->right);

        ret += abs(left - right);
        return root->val + left + right;
    }
};